Snubbing circuits for semaphore signals



1927. May 3K1 y J. E. sTEPHl-:NsoN

SNUBBING CIRCUITS FOR SEMAPHORE SIGNALSA Filed May 25. 1925A Patented May 31, 1927.

Nunirse stares earsia'rforrics.

JAMES E. STEPHENSON, 0F ROCHESTER, NE'W YORK,HASSIGNR TO GENERAL RAIL- WAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK. Y

SNUBBING CIRCUITS FOR SEMAPHORE SIGr1\`I'.A`.[S.

Application ledrMay 25,

This invention relates to railwaysignaling and more. particularly concerns a circuit arrangement. for use in connection with the usual motorv operated semaphore signals of railways.

In modern railway practice, particularly on railroads wherecongested traffic conditions exist, the well known automatic threeposition type of blocksignalingvis often used. In a signaling system of this type, semaphore wayside signals are frequently employed of the type in which the semaphore blade and spectacle are biased to their danger position by gravity or other suitable means, are raised tov their caution and clear positions by a small electric motor and are retained in the caution and clear positions by suitable electrically operatedlat'ching means. lVhen the latching means is released and the semaphore blade with its associated mechanism suddenly biasedfrom a clear or caution position to a caution ordanger position, the momentum 'acquired by the blade and its comparatively heavyspectacle in itheir downward or biased movement causes undueV and injurious strains on the comparatively delicate signal and operating mechanism when this mechanism is brought vto a sudden stop.

lVith the above and other considerations in mind it is proposed in accordance with the present invention tov provide a threeposition semaphore operating mechanism which incorporates means for preventing injurious slamming of partsv whenv the movable signal mechanism is brought to a stop,

and more specifically, it is proposed to provide means in connection with the operating circuits of a signal of this type for dynami cally snubbing the biased motion of the semaphore blade and spectacle by causing a circuit through the operationg motor to be closed through a resistance during the biased motion of the blade. y

yFurther objects, advantages and characteristic features of the presentinvention will become apparent as'the description thereof progresses. n i

In describing the invention in detail, reference will be made to 'the accompanying drawing, in which a single Yligure has been shown, representing in a diagrammatic andV conventional.manner, a ,section of tra'ckway provided with automatic block signals, together with the devices andv circuits for opmechanism and control apparatus'associated with each block is identical` a'detailed descriptionv of that associated with o'ne'block only will be given, the 'corresponding elements associated with the adjacent blocks being referred to. by like reference characters having distinctive exponents. v

Atrack relay 3 is connected across the track rails at the entrance endof each block,

this relay being of/ the Well known polar neutral type, that is, this relay has apolar armature which is biased to one or the other of two positions by the polarity of the current impressed on the relay windings, and

has another' armature which is moved to either one of two positions bythe energization andde-energization of the relay windings, regardless of polarity. The energy for operating the track relay 3y is suppliedby a track battery, 4, loc'ated at the exit end of the block, and connected across the "track rails through the pole changing neutral contacts 51 and '61 of the track relay 31 of the advance block as clearly shown, vso that the polarity of the track circuit lcurrentin a given block will bereversed when the track relay in the next block in advance is deenergized.v Y

of the mechanical vdetails of the signalgoperating mechanism form'no part of the prese-ntk invention.,` and as V,this vstructure is wellA known4 by those skilled in the art, vthe semaphores have been illustratedy in 'a con- Vany other suitable motor might be used, and

it is assumed to be` connected with the semaphore arm through a. suit-able shaft and train of reduction gears. The signal operating mechanism includes two holding coils HandL, of high and low resistances respectively, it being assumed that the energiiation ,of the holding coilvH will serve to retain I 9ov i As the general structure and organization a suitable latcl'iing device in a position to hold thev semaphore blade in its clearl or caution position, but Will not move the latching device to this position.; .While the energization of the holding -coil L will move the latching device from its Jfree or nnengaged position to its engaged posi-tion.

` Suitable contact fingers 9, 10, and ,11, operated in accordance With the position ot the semaphore blade, are provided to controlthe operation oi' the signal mechanism. The linger 9 is arranged co-.engage a stationary Contact segment 12 when the ysemaphore blade is inthe danger position and until jnst before -the blade has reached the caution position, and to engagethe stationary contact 13 justV before Vthe semaphore Vblade reaches its caution position and until just before the blade has reached its clear positioi. rThe contact linger is arranged to engage thefstationary contacts 14 and 15 when the semaphore blade is in its caution and clear positions respectively. The contact linger 11-is arranged to engage'the stationary contact segment 16 justas the blade completes its rmotion from the danger to the caution position, and tri-engage the stationary Contact segment 17.just as the blade completes its motion from the caution to the clear position. The relative position ot' the stationary contact 12 to the stationary7 Vcontact 16, the stationary contact 13 to the stationary contact 17 areso arranged. that the contact linger 11 engages the stationarycontact 16 just before the contact finger 9 disengages the stationary contact 12, and the linger 1.1 engages the' stationary contact 17 just bel'ore the linger 9 disengages the stationary contact 13, also the contact linger 10,

engages its contacts -14 and 15 by the time linger 9 leaves'its contacts 12 and 13 Vrespectively. A

f ,Operation With the block J and the block K inr advance thereof unoccupied, track circuit current ot normal polarity will be impressed Vupon the track rails'ot the'block J and upon the Winding of the track relay 3 througha circuit which may be traced as follows lrom the. vpositive terminal of the track battery 4, front Contact and neutral contact finger 61 of the track relay 31, Wire 18, track resistance 19, Wire 20, one track rail 1 ot the block'J, Wire 21, Windingfot vthe track relay 3W'ire 22, the other track rail ot the block J, Wire 23 `contact linoer. 51 and front con- .29 and back Contact of 'therelay 3,

maintained which circuit may be traced as follows z-rom the positive terminal ol; the

signal operating battery 27, Wire 23, ltrent 'cont-act' and neutral contact linger ot the track relay 3, Wires and 3l, stationary contact 32 and polar contact linger 26 of the track relay 3, Wires 33 and 34, stationary contact andl contact linger-10, Wire 35, Winding of the Vhigh resistance holding coil H, Wires 36 and 37, finger 11. and stationary Contact 17, Wires 38,- 39 and 49,`Windingrot the signal operating motor 3, and Wires 41, 42 and 43 to the negative terminal of 'the battery 27.

J from the Ablock l, the track vcircuit*current Y is shunted from the track relay3V bythe lith the holding` coil H energazed,- the signal mechanism will be main-` Wheels and axles o1 the train and. this relay is consequently cle-energized and retracts its neutral contact lingers 29, 5 and 6. polar Contact linger 26 remains in theposi- Thev tion shown until a current oi' reverie polarity flows in the track relay, I 'W hen the neutral Contact linger. 29 disengages its trent contact, the energizing'circuit to the high resistance holding coil ll, traced above, is broken, vthe latching device is released, and the semaphore blade begins to drop, being biased b y gravityor other suitable means. Shortly after the semaphore blade leaves its clear position, the contact linger 9 engages its stationary contact segment '13, and a snubbing circuit through the operating inotor 3 is completed, which circuit may be traced as folloWsw-t'roin the motor 3, Wires and 44, contact linger 9` and stationary contact y13, Wires 45 and 33, polar Contact linger 26 and stationary contact 32 of the ico track relay 3, VWires 31 and 30, con-tact linger l and 47', snubbing` resistance-flzand Wires 49, 42 and 41 tothe operating niotorSQ The snubbingl resistance T48, included in the circultjust traced, limits the lioiv ot errent generated bythe motor 3 vwhich operates to generate a current in the ivell known iin-inner during'thebiased movement otthe semaphore blade, andthe mechanism "is thereby snubbed or dynamically brakedby the inotor. As the semaphore blade passes thecaiition position, the contactlinger 9 .engages its stationary contact 12 and a second sniibbiiio' circuit for the motorv isV coinpleted,-whcn .Wires 4ol circuit may betraced as follows zti'omthe operating motor l8 Wires 40 and `44, contact linger 9 and stationary Contact V12, wires 5() and 30, contact finger 29 and back contactA of the track relay 3, Wires 46 and 47, snub- 'bing resistance 48, and Wires, 49V. 42 and 4l to the operating motor 8. lt will be notedV iai) Yco

allowed to di'op freely and Was suddenlyV brought to a stop in its danger position.

As the train passes out ot the block il and into the block K, the shunt is removed -troni the track rails oit' the block .l and the neutral contact fingers 29, 5 andG ot the track relay 3 are picked up, picking up ot' track relay ringer 29 breaking the snubbing circuit through motor 8. The train being located in ythe block K, the. track relay 31 ot that block vis de-energized, and its iieuti'al contact lingers 51 and (il are retracted, reversing the polarity ot' the track circuit current 'in the block J through a circuit which is obvious trom the drawings;

i I The track relay 3 ot the block J being supplied with a cur rent of reverse polarity, attracts its polar contact linger 26 to the reversed position, that is, the position" shoivn'by the dotted line, and an energizing circuit tor the signal operating motor 8 is completed., which circuit may be traced as tolloivs:-tiom t-lie .positive terminal of the battery 27, Wire 28,

front contact and neutral contact linger 29, Wir-es and 5,0, stationary contact 12 and contact linger 9, Wires 44 and 40, Winding vot'lthe signal operating motor 8, and Wires 41, 42 and 43 to the negative terminal of the ,battery/'27. The motor 8' being thus energized operates the signal mechanism and raises the `semaphore blade to its caution position; Just before the signal has reached lthe caution position, and betere the contact linger 9 has disengaged the stationary contact 12, the linger ,11engagesl rthe `stationary "contact 16 and a circuit `for energizing the loiv'resistance holding coil Lis completed, which circuit may be traced as follows:- from the positive terminal et the battery 27, iv're -28,"tront cont'actand neutral contact linger 29 of the track relay 3, Wires '30 and 50, stationary contact 12 and contact linger 9 ivires 44, 39 and 51, stationary contact .16 and contact linger 11, wires 37. and 52, Winding of the loW resistance holdingcoil L and'ivires 53, 42'and 43 to the negative terminal of the lbattery 27.Y The .low resistance holding coil L noiv picks up the latching'device to hold the signal mechanism in its caution position, and asthe kmechanism reaches this position `an energizing circuit lfor the high resistance holding coil H is completed, Which circuit may be'traced as follows :-`-trom the positive terminal of the battery 27, Wire 28, Jiront contact and neutral contact linger 29 ot the track relay 3, Wires 30, and 54, stationary contact 14 and contact linger 10, Wire 3.5, Winding of the high resistance holding coil H, Wires 3G and 37, contact linger 11 and stationary contact 16, ivires 51,39 "f and 40,`ivinding oi'ttlie operating inotor 3 and ivii'es 41, 42 yand 43 tothe negative tern'iinal 'ot the battery 27. The circuit through the loiv resistance holding coil L, traced above, is biokeii just beitore the signal reaches the caution position by the disengagement ot' the contact finger 9 and the statioiiary contact 12, so that only the small amount ot' current necessary to energize the high resistance holding coil His. tloiving when the signalmechanism isnot in actual operation, tnis arrangement eli'ecting a vdesirable saving in theainount' sinned. n

Just' before the signal 7 reaches its caution Aposition linger 9` breaks contact with 12, and 'thus interrupts the inotorcircuit traced above. .f f

.fis the train passes out ot the block K,

the track relay 31 ot this block is again energized, attracting its neutral contact 'linger 5'l and (Si, and causing trackrcircuit current ot normal polarity to'lloiv -in the block J. The Dolar contact linger 2G ol the track relay 3 is noiv inoved to its` normal position as shown, and the sign al mechanism Vis operated to its clear position in a -inanner ol energy cousimilar to that desc'ribedabove in' connectionV with the operation troni the danger to the caution position. `rlllie operatingniotor 3 is` energized through afcircuit which inayvbe traced as follou'sz-t'roin `the positive te`r ininal ot the battery 2, `ivire 23, tront con-' tact and neutral contact-linger 29 ol the track relay 3, wires and 3l, stationary contact 32 and polar-contact 26 o't'vthe track relay 3, Wires 33 and 45,`statioiiary 'contact 13 and contact linger 9, vvires 44 and'4li,

ivindings of the operating motor-'S and 'Wires 41, 42 and 43V to the negative terminal of the nisni to its clear position, and just betere' the clear position is reached, an energizing `circuit 'tor the loiv resistance holding coilf'L i lo battery 27. rEhe motor 3 drives the mechas` Wires 30 and 31, stationary'contact 32 and polar contact linger 2G ot the relay 3, ivires 33 and 45, stationarycontact'13 and vcontact `linger 9, `Wires 44, 39 andV 3S, stationary con vtact 1LT-and Contact finger 11, Wires 3T andi52,

ivindingot the loiv k,resistance rholding coil L and ivires 53, 42 and 43 tothe negative terminal oit the battery 2T. The loiv resistance and at this timean'energizing circuit Jtor the l Vholding coilL is de-energized as the signal y eaY high resista-nce holding coil H is completed, which circuit has been traced above.

It should be understood that the latching device used restricts the motion of the signal mechanism in one direction only, that is,'its motion from clear to caution orV caution to danger position, and when the motor is energized tov litt the semaphore plate from its danger to its caution position or lfroin its caution to its clear position, the energization of the-high resistance holding coil ll vvilldnot preventtlie upward motion olf the blade. rThe circuit through the holding coil is'broken as soon as the semaphore blade has started to move by the disengagement ot the stationary contacts let or l5 vby the Contact linger l0, so. that the latching device does not drag, andr energy for the coil H is'not wast-ed. y f

it sometimes occurs that trallic conditions y in a given block change from clearto danger by reason ot the breaking ot a track rail, the opening of a tiack switch or the backing of a train into the block. Assuming that traliic conditions have in this Y manner changed from clear to danger in a given bloclnsay the block K, the track relay 31 at the entrance end ot this blockis Cle-energized, detracting itsV contact lingers 51 and 6 1, and reversing the polarity-ot' the track circuit current tloiving through the track relay 3 ol' the bloclil. The polar contact linger 26 ot the track ielay 3 now assumes its` reverse position as rep'- reeented by the dotted line, thereby breakin the energizing circuit in the holding coil H, .which circuit has been traced above, and so releasing the signalv blade operating mochanism. As the Vsignal blade is moved by gravity toward itsrcaution position, a'snubbine` circuit through the motor 8 isv coinpleted`,`\vhich circuit may be traced as tot lows :.-efrom the snubbing resistance 4S, wire 47, stationary contact 5 5 and contact linger 26 ofthe track relay 3, Wires 33 and 45, stationary Contact 13 and movable contact finger 9, Wires eet and 40, Winding ot the motor 8, and Wires ell, 42 and 49 to the snub bing resistance 48. The signal blade continues its downward motion, being yieldingly resisted 'by the snubbing oi' the motor S, until it has passed beyond the caution position, ivhen the snubbing circuit, traced above, .is broken by the disengagement ot` the contact finger 9 and the stationary contact 13.'

When the signal blade moves affeiv degrees beyond the lcaution position, the contact linger V9 engages its stationary contactV 12,'

andl an energizing circuit for the motor S is coi-iipleted, ivhich circuit may be traced as tolloiyst-roin lthe positive terminal ot .the battery VV27, wire 28, front contact and contact finger 29 otthe track relay 3, Wires 30 and ,50, stationary contact l2 and contact linger 9', Wires 44 and 40, motor 8, and Wires lL-l2Y and43 tothe negative terminal of the battery `27. The motor Sinoiv operates to move the signal blade to its caution position,

and as the caution position is reached, an energizing circuit for the loiv resistance holding coil L is completed through the stationary contact 16 of the movable contact, n

this circuit having been'traced above. The latching device is operated by the energizetion ot the holding Acoil L to maintain the signal blade in its caution position, and, as the signal blade comes to astop in itscaution position, the energizing circuittor the lo7 resistance holding coil L is broken hy the disengagement oit the stationary contact 'l2 and theinovable contactlinger 9, and an energizing circuit for the high resistance holding coil l-l. is completed through the contact linger l0 and thestationary Contact 14, this energizing circuit having been traced 1 Y i n v aoove. lt is :thus `evident that when t-he signal blade moves trom its clear to rits caution positioin'a snubbing circuit through the niotor 8 is completed and* the motion of oi' retarded by the dynamic b raking'eli'eot ob tained by closing the operating motor circuit through a resista-nce duringfsuch biasedl inotion of the mechanism. tion imparts a smooth and slow motion to the semaphore blade'an-d its associated mechanism, and substantially reduces ars, shocks and slams, .thuSinCreasing the lil'e of the Yvarious parts of the mechanism. 'i

rlhe present invention' has been shown and described in connection With rather specific circuits and'devices, and 'it should of coursev be understood that the various means shown and described are capable of certain modification and rearrangement Wit-hout departing from the spirit oli' the` present invention as defined by the `appended claims,

What it is desired/,to secure by Letters `Patent yis:- f n l. In a threefposit-ion railway signal,

,means for operating a biased semaphore blade including a motor for moving said blade from itsr biased position, a track relay, an energizing circuit'for said motor,

and a snubbing circuit for short circuiting the motor through av resistancein series vvith a contact ot the .track relayuhile said semaphore blade moves to its biased position.

2.y In a semaphore railway signal of the tiiree positiony type7 a .semaphore blade biased to its danger position, a motor for moving said blade to its caution or clear positions and means Vtor controlling theoperation osaid motor and said bladecomprising This snubbing aclul) izo

contacts operated in accordance with the position of said blade and contacts operated by a polar neutral relay for energizing said motor to move .said blade under certain conditions and ttor connecting said motor in series with a. resistance :tor opposing the biased motion of said blade under other conditions.

3. In a semaphore railway signal of the three-position type, a semaphore blade biased to its danger position, a nic-tor for moving said blade to its caution or'clear positions and means for controlling the operation of' saidinotor and said blade comprising contacts operated in accordance with the position of said blade and contacts operated by a pola-r neutral relay and circuits controlled by said contacts for energizing said motor to move said blade to the caution positionV when said relay is energized by current of a certain polarity, for energizing said motor to move said blade to the clear position when said` relay is energized by current of an opposite polarity and for closing a series snubhing circuit through said motor to yieldingvly resist thebiased motion of said blade when said relay is ycle-energized.

4. In a railway semaphore signal having clear, caution and danger indicating positions, a semaphore blade biased to its dangerA indicating position, an electric motor for moving said blade to its caution and-clear positions, a pick-up coil and a holding coil acting when energized to respectively operate and maintain operated a means for retaining said blade in its caution or clear positions, a resistance unit, and a polar neutral relayfor controlling the energization of said motor and Vsaid coils and for closing a series circuit through said motor and said resistance unit when said holding coil is deenergized. to permit said blade to be biased :from its vclear orcaution positions to its danger position. p Y y 5. In a railwaysignal of the type having a semaphore blademovable to three indicating positions and biased to one of its extreme positions, a motor for lifting said blade from its biased positon'to either of its other two indicating positions, means for maintaining said blade in leither of said other two positions, a track relay, and means to short circuit the motor through a contact of the track relay for opposing the biased motion of said blade. Y

In testimony whereofIhereby aiiix my signature. l

JAMES EASTEPI-IENSON, 

